An oxygen concentrating apparatus is an apparatus which separates and concentrates oxygen from ambient air and is widely used for domestic use, industrial use, medical use or the like.
Various types of an oxygen concentrating apparatus are used, and a pressure swing adsorption (PSA) type among them is based on a principle of separating and concentrating oxygen using absorbent and adsorbs nitrogen in the air using absorbent to increase the concentration of oxygen. Since the PSA type uses only the pressurized air and the absorbent, it doesn't emit pollutant and can be easily used, so it is widely used.
The absorbent which is generally used in an oxygen concentrating apparatus using a pressure swing adsorption process is synthetic Zeolite. Nitrogen is more easily adsorbed in Zeolite under a relatively high pressure than oxygen. Gas having a relatively high concentration of oxygen is obtained using this property.
At this time, if the Zeolite adsorbs nitrogen, an adsorption capacity thereof becomes deteriorated, so it is necessary to desorb nitrogen from the Zeolite to restore the original adsorption capacity.
For the adsorption of nitrogen, the pressurized air is supplied to an adsorption bed which is filled with absorbent, but at this time water may be generated during the pressurization of air. If the Zeolite is exposed to the pressurized air with water, the nitrogen adsorption capacity of the Zeolite is deteriorated, and the durability is deteriorated due to the pressure change during the PSA process so that the particle of the Zeolite may be worn out or broken.
In order to solve these problems the oxygen concentrating apparatus of the pressure swing adsorption type has a water removing unit. For example, a adsorption water removing method (Korean Patent Publication No. 10-2000-0030484) of passing the pressurized air through a water removing device having accumulated water drying agent such as silica gel or alumina or a freezing water removing method (Korean Patent Publication No. 10-2003-0017054) of reducing the temperature of dew point of the pressurized air to condense water of air has been introduced.
However, in the conventional art, the water removing process is performed independent from the oxygen concentrating processes, so the efficiency may be deteriorated. Further, the water removing device is formed as an independent part from the pressurized air flowing part, so the overall volume is increased. Further, there is a problem in that additional parts for removing water such as water filter should be provided.